The present invention relates to a control device for the control of stepping motors for the adjustment of a motor vehicle seat.
A control device of this generic type is disclosed in German patent document DE 2,836,004 C2. In addition to a tiltable switch actuating element for the backrest adjustment, it contains a switch actuating element for seat height adjustment and longitudinal adjustment of the seat, which can be: (i) displaced in the horizontal direction in order to move the complete vehicle seat forwards or backwards, (ii) displaced in the vertical direction in order to change the seat height, and (iii) swivelled about a horizontal axis in order to change the relative height position between the front edge and the rear edge of the seat cushion. The switch actuating elements are arranged in such a way that, in the plan view, they represent symbols of the outlines of a seat with backrest and seat cushion.
A possible arrangement of the electric switching means in a control device of the generic type is described in German patent document DE 2,839,367 C2. Another known control device disclosed in German patent document DE 3,513,050 A1 has symbols for backrest and seat cushion which are not movable; however, separate switch actuating elements are provided which are moveable in obvious directions relative to the symbols in order to actuate electric switching means. By "obvious directions" it is meant that the movement of the switch relative to the orientation of the symbolic representation of the seat corresponds to the direction of desired movement of the seat itself.
An arrangement of switch actuating elements of a seat adjustment switch is also disclosed in German patent document EF 0,260,213, A2, in which the outlines of backrest and seat cushion are likewise reflected symbolically by the switch actuating elements, the seat cushion being represented by a total of four switch actuating elements arranged quadrantally. To actuate the electric switching elements, the switch actuating elements must be pressed, it being possible for different setting functions to be controlled by simultaneous operation of two actuating elements and by operation of individual actuating elements.
A fourth known control device for seat adjustment, described in German patent document DE 8,516,069 U1 likewise has a frame-like switch actuating element symbolizing a seat cushion, which switch actuating element is displaceable in an obvious direction for the longitudinal adjustment of the seat as a whole. Two further depressible switch actuating elements are integrated into said switch actuating element, of which one serves for raising and the other for lowering the seat. The latter arrangement--which is no longer operable in an obvious sense--forms in function a single change-over contact with a central position and two different actuating elements.
With the control devices described in the latter three publications, only those seat adjustment functions described with respect to the control device of the aforementioned generic type can be controlled.
In German patent document DE 3,631,872 C1 a vehicle seat is described in which the "seat depth" (that is to say the distance between the front edge of the seat and the backrest) can be changed electromotively or by hand to adapt to different thigh lengths of the respective passengers. In addition to the mechanical alternative of a "handwheel", in this publication, however, no device is disclosed for the manual control of the electromotive seat depth change. In another known vehicle seat, described in German patent document DE 3,018,323 C2, the seat depth can likewise be adjusted electromotively or hydraulically; in the latter publication, however, again no means are disclosed for the manual control of the adjustment drives.
The object of the present invention is to develop a control device of the generic type in which the further function "adjust seat depth" can be implemented whilst retaining its obvious operability.
This object is achieved according to the invention by division of the actuating element for the seat cushion adjustment in such a manner that it is possible not only to push the complete seat forwards or backwards by displacing at least the one part of the actuating element as previously known, but also to change the seat depth by displacing at least the other part of the actuating element, while at the same time retaining the obvious correlation between movement of the actuating element and the desired movement of the seat. The adjustment possibilities already mentioned and already hitherto available are, of course, also maintained by means of the two-part switch actuating element according to the invention.
The purpose of such a switch actuating element, which is preferably subdivided horizontally in the installation position, becomes evident to any operator if the seat depth adjustment is allocated to the top part of the switch actuating element and the longitudinal adjustment of the position of the seat is allocated to its bottom part, because the operator can readily associate the seat cushion surface facing him/her--which he/she can lengthen or shorten--to the top part and can associate the chassis of the entire seat to the bottom part.
It can be advantageous in terms of user-friendliness to design the two parts of the actuating element for the control of the adjustment of the seat depth so as to be displaceable at the same time, but in opposite directions, with appropriate contact assignment in order to be able to select the seat depth change obviously with the switch actuating element. In further preferred shaping of the actuating element parts, this opposite displacement of the parts ca result in a lengthening or a shortening of the overall length of the actuating element from a neutral basic position, which at the moment of operation likewise corresponds exactly to the desired adjustment function. This operation in opposite directions can readily be effected by a "shearing movement" of the thumb and one finger of the operator's hand. It also largely prevents both parts of the actuating element from being inadvertently displaced upwards or downwards during the seat depth adjustment and thus prevents unintentional upward or downward seat adjustment from being triggered.
The customary longitudinal adjustment of the seat in the passenger compartment can again be controlled advantageously in the previously mentioned embodiments by displacing the entire actuating element, that is to say displacement of both actuating element parts simultaneously and in opposite direction, if the electric switching means for the longitudinal adjustment are also assigned to both actuating element parts.
In a further embodiment of the invention, the seat depth adjustment is interpreted starting from another aspect. Since the change in seat depth, as already defined, relates in any case to the distance between the front edge of the seat and the backrest, it can also be considered as a relative displacement of the backrest in relation to the seat cushion or its front edge, irrespective of whether the backrest is fixed and the seat cushion is completely or partially displaced, as corresponds to the customary implementation, or whether the seat cushion is fixed and the backrest is displaced. According to this consideration, a surprisingly simple extension of the control device of the generic type for seat depth adjustment is found in the fact that the actuating element symbolizing the backrest, which could hitherto only be swivelled, is now additionally arranged or guided so as to be displaceable, and the switching means for the seat depth adjustment are assigned to the displacement movement of this actuating element. Preferably, but not necessarily, the displacement movement of this actuating element is naturally guided along the longitudinal extension of the single-part actuating element symbolizing the seat cushion in order to achieve, in this case too, an obvious operation and control of the desired adjustment movement of the seat.
In still another embodiment, a second function level, a double assignment so to speak, is assigned to a single-part actuating element for the longitudinal adjustment of the seat by the fact that the switching mean for the seat depth adjustment are also directly assigned to said actuating element. In this case it is particularly advantageous to provide for both adjustments only one set of electric switching means which can be switched over via a change-over device, which is actuated at the same time, by depressing or pulling out the actuating element from the basic position--in which it preferably controls the longitudinal adjustment of the seat.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.